var upH = 10; // Height of up-arrow
var upW = 9; // Width of up-arrow
var downH = 10; // Height of down-arrow
var downW = 9; // Width of down-arrow
var knobH = 12; // Height of scrollbar
var knobW = 9; // Width of scrollbar
//var scrollH = 280; // Height of scrollpath -- declared outside of this file
var speed = 6; // Scroll speed

// Browser detection
var dom = document.getElementById ? true:false;
var nn4 = document.layers ? true:false;
var ie4 = document.all ? true:false;

var mouseY; // Mouse Y position onclick
var mouseX; // Mouse X position onclick

var clickUp = false; // If click on up-arrow
var clickDown = false; // If click on down-arrow
var clickknob = false; // If click on scrollbar
var clickAbove = false; // If click above scrollbar
var clickBelow = false; // If click below scrollbar

var timer = setTimeout("",500); // Repeat variable
var upL; // Up-arrow X
var upT; // Up-arrow Y
var downL; // Down-arrow X
var downT; // Down-arrow Y
var knobL; // Scrollbar X
var knobT; // Scrollbar Y
var scrollbarL; // scrollbar X
var scrollbarT; // scrollbar Y
var contentT; // Content layer Y;
var contentH; // Content height
var contentClippingH; // Content clip height
var scrollLength; // Number of pixels scrollbar should move
var startY; // Keeps track of offset between mouse and span

// Mousedown
function down(e){
	if((document.layers && e.which!=1) || (document.all && event.button!=1)) return true; // Enables the right mousebutton
	getMouse(e);
	startY = (mouseY - knobT);
	
	// If click on up-arrow
	if(mouseX >= upL && (mouseX <= (upL + upW)) && mouseY >= upT && (mouseY <= (upT + upH))){
		clickUp = true;
		return scrollUp();
	}	
	// Else if click on down-arrow
	else if(mouseX >= downL && (mouseX <= (downL + downW)) && mouseY >= downT && (mouseY <= (downT + downH))){
		clickDown = true;
		return scrollDown();
	}
	// Else if click on scrollbar
	else if(mouseX >= knobL && (mouseX <= (knobL + knobW)) && mouseY >= knobT && (mouseY <= (knobT + knobH))){
		clickknob = true;
		return false;
	}
	else if(mouseX >= knobL && (mouseX <= (knobL + knobW)) && mouseY >= scrollbarT && (mouseY <= (scrollbarT + scrollH))){
		// If click above knob
		if(mouseY < knobT){
			clickAbove = true;
			clickUp = true;
			return scrollUp();
		}
		// Else click below knob
		else{
			clickBelow = true;
			clickDown = true;
			return scrollDown();
		}
	}
	// If no scrolling is to take place
	else{
		return true;
	}
}

// knob function
function move(e){
	if(clickknob && contentH > contentClippingH){
		getMouse(e);
		knobT = (mouseY - startY);
		
		if(knobT < (scrollbarT))
			knobT = scrollbarT;		
		if(knobT > (scrollbarT + scrollH - knobH))
			knobT = (scrollbarT + scrollH - knobH);
		
		contentT = ((knobT - scrollbarT)*(1/scrollLength));
		contentT = eval('-' + contentT);

		moveTo();
		
		// So ie-pc doesn't select gifs
		if(ie4)
			return false;
	}
}

function up(){
	clearTimeout(timer);
	// Resetting variables
	clickUp = false;
	clickDown = false;
	clickknob = false;
	clickAbove = false;
	clickBelow = false;
	return true;
}

// Reads content layer top
function getT(){
	if(ie4)
		contentT = document.all.content.style.pixelTop;
	else if(nn4)
		contentT = document.contentClipping.document.content.top;
	else if(dom)
		contentT = parseInt(document.getElementById("content").style.top);
}

// Reads mouse X and Y coordinates
function getMouse(e){
	if(ie4){
		mouseY = event.clientY + document.body.scrollTop;
		mouseX = event.clientX + document.body.scrollLeft;
	}
	else if(nn4 || dom){
		mouseY = e.pageY;
		mouseX = e.pageX;
	}
}

// Moves the layer
function moveTo(){
	if(ie4){
		document.all.content.style.top = contentT;
		document.all.scrollbar.style.top = knobT;
		document.all.knob.style.top = knobT;
	}
	else if(nn4){
		document.contentClipping.document.content.top = contentT;
		document.scrollbar.top = knobT;
		document.knob.top = knobT;
	}
	else if(dom){
		document.getElementById("content").style.top = contentT + "px";
		document.getElementById("knob").style.top = knobT + "px";
		document.getElementById("scrollbar").style.top = knobT + "px";
	}
}

// Scrolls up
function scrollUp(){
	getT();
	
	if(clickAbove){
		if(knobT <= (mouseY-(knobH/2)))
			return up();
	}
	
	if(clickUp){
		if(contentT < 0){		
			knobT = knobT - (speed*scrollLength);
			
			if(knobT < (scrollbarT))
				knobT = scrollbarT;
				
			contentT = contentT + speed;
			if(contentT > 0)
				contentT = 0;
			
			moveTo();
			timer = setTimeout("scrollUp()",25);
		}
	}
	return false;
}

// Scrolls down
function scrollDown(){
	getT();
	
	if(clickBelow){
		if(knobT >= (mouseY-(knobH/2)))
			return up();
	}

	if(clickDown){
		if(contentT > -(contentH - contentClippingH)){			
			knobT = knobT + (speed*scrollLength);
			if(knobT > (scrollbarT + scrollH - knobH))
				knobT = (scrollbarT + scrollH - knobH);
			
			contentT = contentT - speed;
			if(contentT < -(contentH - contentClippingH))
				contentT = -(contentH - contentClippingH);
			
			moveTo();
			timer = setTimeout("scrollDown()",25);
		}
	}
	return false;
}

// reloads page to position the layers again
function reloadPage(){
	location.reload();
}

// Preload
function eventLoader(){
	if(ie4){
		// Up-arrow X and Y variables
		if ((document.all.up) && (document.all.up.style.pixelLeft)) {
			upL = document.all.up.style.pixelLeft;
			upT = document.all.up.style.pixelTop;
		}
		// Down-arrow X and Y variables
		if ((document.all.down) && (document.all.down.style.pixelLeft)) {
			downL = document.all.down.style.pixelLeft;
			downT = document.all.down.style.pixelTop;
		}
		// Scrollbar X and Y variables
		if ((document.all.knob) && (document.all.knob.style.pixelLeft)) {
			knobL = document.all.knob.style.pixelLeft;
			knobT = document.all.knob.style.pixelTop;	
		}
		// scrollbar Y variable
		if ((document.all.scrollbar) && (document.all.scrollbar.style.pixelLeft)) {
			scrollbarT = document.all.scrollbar.style.pixelTop;		
		}
		// Height of content layer and clip layer
		contentH = parseInt(document.all.content.scrollHeight);
		contentClippingH = parseInt(document.all.contentClipping.style.height);
	}
	else if(nn4){
		// Up-arrow X and Y variables
		upL = document.up.left;
		upT = document.up.top;		
		// Down-arrow X and Y variables
		downL = document.down.left;
		downT = document.down.top;		
		// Scrollbar X and Y variables
		knobL = document.knob.left;
		knobT = document.knob.top;		
		// scrollbar Y variable
		scrollbarT = document.scrollbar.top;
		// Height of content layer and clip layer
		contentH = document.contentClipping.document.content.clip.bottom;
		contentClippingH = document.contentClipping.clip.bottom;
	}
	else if(dom){
		// Up-arrow X and Y variables
		upL = parseInt(document.getElementById("up").style.left);
		upT = parseInt(document.getElementById("up").style.top);
		// Down-arrow X and Y variables
		downL = parseInt(document.getElementById("down").style.left);
		downT = parseInt(document.getElementById("down").style.top);
		// Scrollbar X and Y variables
		knobL = parseInt(document.getElementById("knob").style.left);
		knobT = parseInt(document.getElementById("knob").style.top);
		// scrollbar Y variable
		scrollbarT = parseInt(document.getElementById("scrollbar").style.top);
		// Height of content layer and clip layer
		contentH = parseInt(document.getElementById("content").offsetHeight);
		contentClippingH = parseInt(document.getElementById("contentClipping").offsetHeight);
		document.getElementById("content").style.top = 0 + "px";
		
	}
	// Number of pixels scrollbar should move
	scrollLength = ((scrollH-knobH)/(contentH-contentClippingH));
	// Initializes event capturing
	if(nn4){
		document.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE | Event.MOUSEUP);
		window.onresize = reloadPage;
	}
	document.onmousedown = down;
	document.onmousemove = move;
	document.onmouseup = up;
	
	if(contentH <= contentClippingH){
		document.getElementById("scrollbar").style.visibility = "hidden";
		document.getElementById("knob").style.visibility = "hidden";
		document.getElementById("scrollpath").style.visibility = "hidden";
		document.getElementById("up").style.visibility = "hidden";
		document.getElementById("down").style.visibility = "hidden";
	}
}